Tuesday, May 3, 2016

What is the custom ROM and the custom kernel of an Android OS

Android Beginners Q&A

A ROM would be considered the complete operating system (think MS Windows, Mac OSX) - in this case a version of the Android operating system. All of these operating systems have a section of code, which is called the kernel. The kernel is responsible for numerous things within the OS, mostly distributing processing capabilities in between programs (scheduling). When it comes to "custom"-ROM or kernels within the Android community, people are referring to complete Software packages (Cyanogenmod, Paranoid-Android etc) or kernels that are aftermarket software and not shipped by the manufacturer. A custom kernel would be that section of the OS only, that is handling scheduling etc. Both these things are in contrast to "stock Android", which is what ships on the respective Android devices.You can flash (install) a custom kernel onto a stock ROM to potentially improve performance/battery life etc, depending on what the person that developed said kernels is trying to achieve with it (i.e. more aggressive scheduling, overclocking, undervaluing etc.)Hope this clarifies things for you.

Getting The Right Custom ROM

New phones and ROMs come out all the time, and the scope of this article doesn't cover individual ROMs - but the general approach to finding one is Googling for "YOUR_PHONE_MODEL ROM" or something similar, optionally including the wanted Android version. Try it out - you'll find what you want.

How to Find Custom ROMs for Your Android Phone

AOSP variants

Google releases the “pure” version of Android to the world though
something called the Android Open Source Project. Generally speaking
you’re not going to find ROMs for your phone or tablet in the AOSP.
Instead you’ll find the source code of Android so you (or another
developer) can bake your own version of Android however you’d like.

Since you, as an individual, probably aren’t going to build your own
ROM, you’ll likely use a ROM that’s built by another developer, or group
of developers. Here are some of the more popular ROMs based on AOSP.

CyanogenMod

CyanogenMod ROM has been around since the very early days of Android
and has one of the longest “supported devices” lists around. Back in the
day CyanogenMod (abbreviated to “CM”) would push the envelope and offer
all kinds of new customizations and features. Recently they’ve switched
their focus to stability and compatibility as their primary objectives,
with customization and improvements being less important.

Paranoid Android

Paranoid Android, or “PA” for short, grew from “a basic environment …
with a bunch of little hacks and apps to make it usable on XHDPI
devices … (followed by) framework modifications” and eventually what’s
known as their “Hybrid Engine”. This ROM lets you hyper-customize how
your apps look, and whether you want them to be laid out in phone.

Why do I need to flash stock or custom ROMs to my Android device?

There are several reasons to be looking for a ROM:

Upgrading or downgrading your stock ROM

Looking for firmware from a different region/language

Flashing a custom ROM for different features, removing bloat, etc.

But where can one find ROMs in the first place? What sites are likely to have the ROM I need?